Low, movable partitions have become the standard method of providing individual space cubicles for millions of office workers throughout the world. The principal deficiency with all low participation systems is the lack of acoustical privacy. If a worker in a cubicle is able to hear what is said in the next cubicle, it may be hard to concentrate and result in the loss of efficiency and productivity. This invention consists of a sound diffraction device to be installed on the top of movable office partitions. The addition of this invention improves the acoustical performance of movable office partitions.